Relationship between the unique microstructures and behaviors of high-entropy alloys

High-entropy alloys(HEAs),which were introduced as a pioneering concept in 2004,have captured the keen interest of nu-merous researchers.Entropy,in this context,can be perceived as representing disorder and randomness.By contrast,elemental composi-tions within alloy systems occupy specific structural sites in space,a concept referred to as structure.In accordance with Shannon entropy,structure is analogous to information.Generally,the arrangement of atoms within a material,termed its structure,plays a pivotal role in dictating its properties.In addition to expanding the array of options for alloy composites,HEAs afford ample opportunities for diverse structural designs.The profound influence of distinct structural features on the exceptional behaviors of alloys is underscored by numer-ous examples.These features include remarkably high fracture strength with excellent ductility,antiballistic capability,exceptional radi-ation resistance,and corrosion resistance.In this paper,we delve into various unique material structures and properties while elucidating the intricate relationship between structure and performance.

Co_(47.5)Fe_(28.·5)Ni_(19)Si_(3.3)Al_(1.7)High-entropy Skeletons Fabricated by Selective Laser Melting and Properties tuned by pressure infiltration of Al

High saturation magnetization and low coercivity are required for soft magnetic materials.This study investigated the Co_(47.5)Fe_(28.5)Ni_(19)Si_(3.3)Al_(1.7)high-entropy soft magnetic skeleton was prepared by selective laser melting.Then Al wpressure infiltrated into skeletons to obtain a dense composite material.The high-entropy composite materials possessed favorable compressive ductility and moderate soft magnetic properties.The high-entropy composite materials were obtained with Ms being 97.1 emu/g,79.8 emu/g,33 emu/g and possessing 19 Oe,15.8Oe and 17Oe of Hc,respectively.However,the magnetostriction coefficient remains low level,about 5ppm.These reported properties are attributed to the special structure of the material studied in present experiment.Nevertheless,a novel strategy of structural designing was proposed in this paper.

Effect of electric pulse rolling on plastic forming ability of AZ91D magnesium alloy

AZ91D magnesium alloy rolled under four rolling conditions,namely cold rolling,electric pulsecold rolling,hot rolling and electric pulse hot rolling,and the first principles calculation of Mg with or without external electric field carried out.The results show that:The application of pulse current in the rolling process of AZ91D magnesium alloy can effectively improve the edge crack of the sample,optimize the texture of AZ91D magnesium alloy and reduce its texture strength,promote the generation of tensile twins and the transition from small Angle grain boundaries to large Angle grain boundaries,and thus improve the plastic forming ability of AZ91D magnesium alloy.Make it more prone to plastic deformation.Compared with ordinary rolling,the microhardness ofα-Mg matrix decreases by 15%.The tensile strength and elongation increased from 137MPa and 3.4%to 169MPa and 4.7%,respectively.The results show that the stiffness of Mg decreases and the Poisson's ratio of Mg increases when the electric field applies.When the B/G value is greater than 1.75,the plasticity of Mg is improved.The fault energy at the base surface of Mg does not change much,while the fault energy at the prismatic surface of Mg decreases obviously,showing the external electric field mainly affects the prismatic surface slip of Mg,which makes the prismatic surface slip easier to start,and thus improves the plastic forming ability of Mg.